Abstract Receiver has been a basic block in communication systems since the late 19th century.Nowadays,with the development of wireless communication, receiver has acquired an essential role in engineer's mind.receiver's main function is to recover the signals from the transmitted waves and convert them to electronic signals. Automatic gain control(AGC),as a necessary part of receiver,has a main function to adjust the power of signals,which can keep the output signal stable while the input signals change in a wide range.In order to implement this function,AGC needs to control the gain of all the variable gain blocks in the receiver.Because of the invention of fully integrated receiver,it has been a new problem to set the gain of each variable gain blocks.In this dissertation we make a discussion of noise and distortion in detail,which are the main interferences in communication.Then we advance a new theory-signal to noise and distortion ratio(SNDR),which can measure signal quality. After a brief introduce of receiver architectures,we can work out a solution to set every variable gain blocks of a TV-tuner,with the help of SNDR and consideration of out-band distortion. This treatise also combines AGC with system control.Give a detail algorithm of system control and AGC in the TV-tuner.And introduce other digital blocks briefly in this chip. Finally,simulation results and measured results are presented,which verified the function of AGC and the chip. Key Words:RF receiver,AGC,SNDR,receiver system control,noise, distortion,CTB VI川VII Abstract Receiver has been a basic block in communication systems since the late 19th century. Nowadays, with the development of wireless communication, receiver has acquired an essential role in engineer’s mind. receiver’s main function is to recover the signals from the transmitted waves and convert them to electronic signals. Automatic gain control (AGC), as a necessary part of receiver, has a main function to adjust the power of signals, which can keep the output signal stable while the input signals change in a wide range. In order to implement this function, AGC needs to control the gain of all the variable gain blocks in the receiver. Because of the invention of fully integrated receiver, it has been a new problem to set the gain of each variable gain blocks. In this dissertation we make a discussion of noise and distortion in detail, which are the main interferences in communication. Then we advance a new theory - signal to noise and distortion ratio (SNDR), which can measure signal quality. After a brief introduce of receiver architectures, we can work out a solution to set every variable gain blocks of a TV-tuner, with the help of SNDR and consideration of out-band distortion. This treatise also combines AGC with system control. Give a detail algorithm of system control and AGC in the TV-tuner. And introduce other digital blocks briefly in this chip. Finally, simulation results and measured results are presented, which verified the function of AGC and the chip. Key Words: RF receiver, AGC, SNDR, receiver system control, noise, distortion, CTB